A lacrimal duct cyst, medically termed dacryocystocele, is an uncommon condition primarily observed in newborn infants. This cystic swelling develops near the inner corner of the eye within the tear drainage system. It forms when a blockage causes tears and fluid to accumulate, resulting in a visible mass. Although often benign, this condition requires attention due to its potential to develop into a serious infection.
Anatomy and Formation of the Cyst
The lacrimal system collects tears from the eye surface and drains them into the nasal cavity. Tears pass through small openings on the eyelids called puncta, travel through canaliculi, and reach the lacrimal sac. This sac sits near the bridge of the nose and leads directly into the nasolacrimal duct (NLD), which carries the fluid into the nose.
A lacrimal duct cyst forms due to blockages at both the top and bottom of the lacrimal sac. The lower blockage typically occurs at the distal end of the NLD, where the Valve of Hasner fails to fully open at birth. This incomplete opening traps fluid within the duct system.
The upper blockage is often functional; fluid accumulation causes the lacrimal sac to distend, creating a one-way valve effect at the sac’s entrance, sometimes involving the Valve of Rosenmuller. This dual obstruction prevents tears and mucoid fluid from draining into the nose or refluxing back up through the puncta. As fluid collects within the lacrimal sac and NLD, the structure swells into a dacryocystocele.
The cyst is a collection of trapped mucoid fluid, sometimes mixed with amniotic fluid, leading to the alternative names amniotocele or mucocele. The underlying cause is thought to be the structural failure to fully canalize the duct system during fetal development. The cyst may also have an intranasal component, presenting as a mass under the inferior turbinate within the nasal cavity.
Recognizable Symptoms and the Risk of Infection
The most prominent sign is a visible, smooth swelling located just below the inner corner of the eye, near the nasal bridge. This mass often appears shortly after birth, typically within the first few weeks of life, and may have a distinctive bluish-gray color due to the thin overlying skin. Unlike a simple nasolacrimal duct obstruction, which causes excessive tearing, a dacryocystocele presents as a palpable, tense mass.
Excessive tearing, known as epiphora, is a common accompanying symptom because tears cannot drain properly into the blocked system. While the uncomplicated cyst is usually not painful or red, its presence creates a stagnant reservoir of fluid. This stagnation makes the cyst highly susceptible to bacterial overgrowth, which can rapidly lead to a secondary infection called dacryocystitis.
Dacryocystitis is a serious complication requiring prompt medical attention, characterized by a dramatic change in the cyst’s appearance. The previously smooth, bluish swelling becomes intensely red, warm to the touch, and tender. Other signs of infection include fever, swelling of the surrounding eyelid, and pus or a thick, purulent discharge from the eye or upon gentle pressure. An untreated infection can progress to a more widespread infection, such as orbital cellulitis, which poses a risk to vision and health.
Diagnosis and Management Options
Diagnosis is primarily clinical, relying on the characteristic appearance of a tense, cystic mass at the inferomedial canthus in a newborn. Professionals may attempt to express the sac’s contents to see if fluid or mucus refluxes through the puncta, helping distinguish it from other masses. While clinical examination is usually sufficient, imaging techniques like ultrasound can confirm the cystic nature of the mass and rule out possibilities such as an encephalocele.
If the cyst is large or an intranasal component causes breathing difficulties, especially in newborns who are obligate nasal breathers, a CT scan or MRI may be performed. These imaging studies delineate the extent of the cyst and assess its relationship with surrounding bone structures, though they may require sedation.
Management of an uncomplicated dacryocystocele often begins with conservative observation, as many cases resolve spontaneously within the first few weeks or months of life. Gentle massage techniques over the lacrimal sac are recommended to increase hydrostatic pressure, which can sometimes force the obstruction at the Valve of Hasner to open. Topical antibiotics may be prescribed prophylactically or if there are mild signs of conjunctivitis.
When the cyst becomes infected, treatment must be more aggressive, often involving hospitalization and systemic intravenous antibiotics to control dacryocystitis. Once the acute infection is managed, the underlying obstruction is addressed with intervention. The most common procedure is nasolacrimal duct probing, where a thin, blunt metal wire is passed through the tear duct system to physically open the blockage at the valve. If simple probing is unsuccessful or the obstruction is complex, procedures like balloon dacryoplasty or temporary nasolacrimal duct intubation may be utilized to keep the drainage pathway open.